1. Field of the invention
The present invention is generally concerned with clutch release bearings, in particular for automobile vehicles.
It is more particularly directed to clutch release bearings of the so-called pull type adapted to operate in traction on the clutch release device of the clutch to be operated and which must be coupled thereto to achieve this.
2. Description of the prior art
In certain clutch release bearing assemblies, and particularly in the clutch release bearing assembly described in U.S. Pat. No. 4,588,061 it is proposed to employ a part hereinafter referred to for convenience as the "coupling part" between the clutch release bearing and the clutch release device to be operated; appropriately fastened to the clutch release device, this part comprises on the side opposite the clutch release bearing a radial bearing flange through which it is adapted to operate on the clutch release bearing, in cooperation with coupling means operative in traction which, disposed between a part referred to hereinafter for convenience as the "drive part" forming part of the clutch release bearing and a part referred to hereinafter for convenience as the "coupling part" are adapted to provide an axial coupling between said parts.
In practice, in the aforementioned patent, the coupling means operative in traction used generally consist of a coupling member which is elastically deformable in the radial direction carried by one of the parts to be fastened together in traction and adapted to cooperate abutment fashion with a drive bearing surface formed generally transversely on the other part for this purpose.
A particular advantage of an arrangement like this is that it makes it possible to fit the coupling part to the clutch release device of the clutch to be operated in advance, before mounting the corresponding clutch cover assembly, and then, at assembly time, to simply interlock the clutch release bearing with the coupling part snap-fastener fashion.
In the embodiments proposed in the aforementioned patent the coupling member is an annular ring referred to hereinafter for convenience as the "coupling ring"; it is at least partially engaged in the radial direction in an annular retaining groove formed on one of the parts to be coupled together in traction, the other of these parts comprising the drive bearing surface with which it has to cooperate to achieve such coupling. The flank of the retaining groove axially opposite the drive bearing surface relative to the coupling ring is generally oblique to the axis of the assembly, diverging from the other flank of the retaining groove. When the clutch release bearing exerts traction on the coupling part through its drive part and, through the intermediary of the coupling part, on the clutch release device of the clutch to be operated, the coupling ring being operative axially between said parts is systematically urged towards the drive bearing surface with which it has to cooperate.
In the abovementioned patent, the part provided with the drive bearing surface comprises, facing the coupling ring, at least one peg projecting away from the drive bearing surface relative to the coupling ring, this peg having a so-called ejection surface that is generally oblique to the axis of the assembly, diverging from the drive bearing surface.
The clutch release bearing+coupling part assembly may then be mounted in the conventional way by simply clipping it on. During demounting it is sufficient to push the coupling ring towards the pegs, using the drive part of the release bearing, the ejection surface of the pegs, being generally oblique to the axis of the assembly, then obliging the ring to retract into the retaining groove that the drive part, for example, features, the coupling ring being adapted to resume its initial shape as soon as the pressure on it has made it pass over the pegs. The coupling ring is then on the opposite side of the coupling part to the clutch release bearing, for example, on the bearing flange that the coupling part features. The release bearing may then be removed, no longer being interlocked with the coupling ring.
The abovementioned patent also concerns a method of mounting a release bearing assembly in which the drive part of the release bearing is snapped into the coupling part with an overtravel, entailing the insertion of the drive part into the coupling part with the drive part insertion travel limited by positioning one or more wedges between the coupling part and the cover of the release bearing to prevent unclipping of the assembly due to ejection of the coupling ring by the peg during mounting. It also concerns a method of demounting a release bearing assembly which entails pushing the coupling ring beyond the peg, the wedge or wedges have been taken out at the end of mounting the assembly.
An implementation of this kind, although satisfactory, requires a large opening to be made in the clutch casing and the wedges to be withdrawn at the end of mounting, not to mention the large number of parts involved.
An object of the present invention is to alleviate this disadvantage by eliminating the use of wedges whilst maintaining highly precise travels.